Help with a hot tub heater testing

Thread Starter

Helpmefixmyphone

Joined Jan 31, 2022
17
Hello.
I was wondering if anyone could help me test my hot tub heater. It's a bestway lay z spa new York with a blue egg.


It doesn't keep it hot any more for some reason. I have disassembled it and there are only a few parts really inside.

Can any anyone tell me if I can test the elements with my multi meter ? I suppose that would be a good place to start?
Ive attached a picture for reference to see.

Thanks for any help.
 

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DickCappels

Joined Aug 21, 2008
10,153
Check for voltage across the heating element, then after unplugging everything check for continuity (low resistance) of the heating element.
 

Alec_t

Joined Sep 17, 2013
14,280
Each element should have a resistance of about 26 Ohms.
Does the system have a fuse or thermal cut-out? If so, hopefully it's a resettable one.
 

Dodgydave

Joined Jun 22, 2012
11,284
If these are separate elements rated at 1kW each, so they should be about 52 ohms . Check the voltage to each element also .
 

Thread Starter

Helpmefixmyphone

Joined Jan 31, 2022
17
Hi,

Yes there is a thermal cut out as attached.
much lower than 52 Ohms , as they are PTC heaters. (See next photo)
Hi all. Thanks for helping. Can I test any of this with out it plugged In or do I need to hook it up to the small descaler unit and have it heating ? It won't start unless it has water flowing.
 

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Alec_t

Joined Sep 17, 2013
14,280
I have put the meter on 2k
Assuming that's the 2k Ohms range then both your readings seem way too high for simple resistive elements. Also, if the two elements have the same Wattage rating (both 2kW?) then they should give the same resistance readings.
So it looks like both elements have failed; which is unusual.
 

Pyrex

Joined Feb 16, 2022
247
PTC is a quite nonlinear heater... Nor sure if 700- 900 Ohm ar room temperature is OK or not.
Disconnect those heaters from the black terminal and apply mains voltage for duration of 3-5 sec. Use a plugged cord for the test. Unplug the cord and test with the hand it's hot or not
 

Thread Starter

Helpmefixmyphone

Joined Jan 31, 2022
17
PTC is a quite nonlinear heater... Nor sure if 700- 900 Ohm ar room temperature is OK or not.
Disconnect those heaters from the black terminal and apply mains voltage for duration of 3-5 sec. Use a plugged cord for the test. Unplug the cord and test with the hand it's hot or not
Hello.
So, I have connected the heater circuit 'A' to a plug and it gets hot.
I let it cool back down.
I connected 'B' circuit to the plug and that also got hot.
 

Pyrex

Joined Feb 16, 2022
247
Hello.
So, I have connected the heater circuit 'A' to a plug and it gets hot.
I let it cool back down.
I connected 'B' circuit to the plug and that also got hot.
So, the thermal switch is OK, and both PTC heaters are OK.
It seems the problem is with regulator. Take out that white plactic cover to find the printed board and make a photo.
And one more suggestion. Do a water flow sensor is installed in this device?
 

Pyrex

Joined Feb 16, 2022
247
A lot of components on PCB to perform such a simple function- to heat up some water...

I suggest you to check the flow switch first. How much cores in the cable? I suggest, there's two cores. If so, disconnect it from the PCB and check with multimeter in Ohm meter mode
 

Thread Starter

Helpmefixmyphone

Joined Jan 31, 2022
17
A lot of components on PCB to perform such a simple function- to heat up some water...

I suggest you to check the flow switch first. How much cores in the cable? I suggest, there's two cores. If so, disconnect it from the PCB and check with multimeter in Ohm meter mode
The flow switch must work as it works on the test rig during descaling procedure. The water heats up a small amount.
Hot tub descaler


It also has blowers and other modes with the blower fan so must be more components for that purpose .
What cable core do you suggest I ohm check?
Thank you for still helping btw.
 

Pyrex

Joined Feb 16, 2022
247
i noted a small fuse in a brown rectangular case ,situated close to the two-coil choke, near to the terminal. Check it first. Use a multimeter in continuity check mode. Simply stub the probes into this jellyish warnish to reach the copper conductors on the PCB
 

Thread Starter

Helpmefixmyphone

Joined Jan 31, 2022
17
Hello:) I tested the fuse. It's ok.

So yesterday I have put it all back together to try it again.
I filled it up with hot water from the gas boiler as it's quicker.

I filled it up to a temperature of about 37 degrees.
The hot tub heater will then only keep the water at that temperature but it will NOT heat it any hotter. It should easily take it to 40 degrees at this time of year.

Could it be the temperature sensors? These are two. A red in the water flow and a blue wire sat next to the heater block

What do you think now?

And thanks for your help again
 
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